Microplastic pollution from synthetic textiles:quantitative evaluation and mitigation strategies

The present thesis focuses on microplastic pollution from synthetic textiles. Microplastics are defined as plastic fragments with dimensions less than 5 mm, which are gaining much attention due to their ubiquitous and possibly dangereous presence in marine environment. Washing processes of synthetic garments have been lately identified as responsible for about 35% of primary microplastic release in oceans and seas. Microplastics represent a threat for marine ecosystems, and consequently for humans, since they may be ingested by fauna, adsorb persistent organic pollutants and leach toxic additives. Moreover, recent concern has arisen regarding the possibility for humans to inhale microplastics released to air from wearing of synthetic garments, with still not understood consequences on health. In such scenario, this work has three major objectives: developing experimental procedures to quantify microfibres released to water and to air from synthetic clothes, investigating the role of textile characteristics and washing conditions in the release of microfibres, implementing mitigation strategies. First of all, two quantitative methods were developed to evaluate the amount of microfibres released during washing processes at lab and real scale. The two developed procedures were compared in terms of results, effectiveness, costs and time consume and proved to be a useful tool for the evaluation of the extent of the release from textiles, allowing the identification of specific trends in the microplastic release, as a function of the textile nature and geometry, different detergents and washing conditions. Then, a protocol involving tests with volunteers wearing commercial synthetic garments was set up to assess if microfibres are actually released by wearing clothes and if the quantities and dimensions pose a real threat for human health. Finally, mitigation actions were proposed, based on the development of innovative finishing treatments of synthetic textiles, aimed at creating a thin coating on the surface of fabrics that could protect them during the stresses of wearing and washing, reducing the release of microfibres. The ecosustainability of such treatments was ensured by using natural or biodegradable polymers as finishing materials, instead of the conventional synthetic ones. The effectiveness of such treatments in mitigating the release of microfibres was tested by washing tests at lab scale, showing a very promising reduction of almost 90% of microfibres released by untreated fabrics.